Split channels library.

pkg/analysis_server/lib/src/channel/byte_stream_channel.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library channel.byte_stream;
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:analysis_server/src/channel/channel.dart';
+import 'package:analysis_server/src/protocol.dart';
+
+/**
+ * Instances of the class [ByteStreamClientChannel] implement a
+ * [ClientCommunicationChannel] that uses a stream and a sink (typically,
+ * standard input and standard output) to communicate with servers.
+ */
+class ByteStreamClientChannel implements ClientCommunicationChannel {
+  final Stream input;
+  final IOSink output;
+
+  @override
+  Stream<Response> responseStream;
+
+  @override
+  Stream<Notification> notificationStream;
+
+  ByteStreamClientChannel(this.input, this.output) {
+    Stream jsonStream = input.transform((new Utf8Codec()).decoder)
+        .transform(new LineSplitter())
+        .transform(new JsonStreamDecoder())
+        .where((json) => json is Map)
+        .asBroadcastStream();
+    responseStream = jsonStream
+        .where((json) => json[Notification.EVENT] == null)
+        .transform(new ResponseConverter())
+        .asBroadcastStream();
+    notificationStream = jsonStream
+        .where((json) => json[Notification.EVENT] != null)
+        .transform(new NotificationConverter())
+        .asBroadcastStream();
+  }
+
+  @override
+  Future close() {
+    return output.close();
+  }
+
+  @override
+  Future<Response> sendRequest(Request request) {
+    String id = request.id;
+    output.writeln(JSON.encode(request.toJson()));
+    return responseStream.firstWhere((Response response) => response.id == id);
+  }
+}
+
+/**
+ * Instances of the class [ByteStreamServerChannel] implement a
+ * [ServerCommunicationChannel] that uses a stream and a sink (typically,
+ * standard input and standard output) to communicate with clients.
+ */
+class ByteStreamServerChannel implements ServerCommunicationChannel {
+  final Stream input;
+  final IOSink output;
+
+  /**
+   * Completer that will be signalled when the input stream is closed.
+   */
+  final Completer _closed = new Completer();
+
+  ByteStreamServerChannel(this.input, this.output);
+
+  /**
+   * Future that will be completed when the input stream is closed.
+   */
+  Future get closed {
+    return _closed.future;
+  }
+
+  @override
+  void close() {
+    if (!_closed.isCompleted) {
+      _closed.complete();
+    }
+  }
+
+  @override
+  void listen(void onRequest(Request request), {Function onError, void
+      onDone()}) {
+    input.transform((new Utf8Codec()).decoder).transform(new LineSplitter()
+        ).listen((String data) => _readRequest(data, onRequest), onError: onError,
+        onDone: () {
+      close();
+      onDone();
+    });
+  }
+
+  @override
+  void sendNotification(Notification notification) {
+    // Don't send any further notifications after the communication channel is
+    // closed.
+    if (_closed.isCompleted) {
+      return;
+    }
+    output.writeln(JSON.encode(notification.toJson()));
+  }
+
+  @override
+  void sendResponse(Response response) {
+    // Don't send any further responses after the communication channel is
+    // closed.
+    if (_closed.isCompleted) {
+      return;
+    }
+    output.writeln(JSON.encode(response.toJson()));
+  }
+
+  /**
+   * Read a request from the given [data] and use the given function to handle
+   * the request.
+   */
+  void _readRequest(Object data, void onRequest(Request request)) {
+    // Ignore any further requests after the communication channel is closed.
+    if (_closed.isCompleted) {
+      return;
+    }
+    // Parse the string as a JSON descriptor and process the resulting
+    // structure as a request.
+    Request request = new Request.fromString(data);
+    if (request == null) {
+      sendResponse(new Response.invalidRequestFormat());
+      return;
+    }
+    onRequest(request);
+  }
+}